Early life history of deep-water gorgonian corals may limit their abundance

PLoS One. 2013 Jun 10;8(6):e65394. doi: 10.1371/journal.pone.0065394. Print 2013.

Abstract

Deep-water gorgonian corals are long-lived organisms found worldwide off continental margins and seamounts, usually occurring at depths of ∼200-1,000 m. Most corals undergo sexual reproduction by releasing a planktonic larval stage that disperses; however, recruitment rates and the environmental and biological factors influencing recruitment in deep-sea species are poorly known. Here, we present results from a 4-year field experiment conducted in the Gulf of Maine (northwest Atlantic) at depths >650 m that document recruitment for 2 species of deep-water gorgonian corals, Primnoa resedaeformis and Paragorgia arborea. The abundance of P. resedaeformis recruits was high, and influenced by the structural complexity of the recipient habitat, but very few recruits of P. arborea were found. We suggest that divergent reproductive modes (P. resedaeformis as a broadcast spawner and P. arborea as a brooder) may explain this pattern. Despite the high recruitment of P. resedaeformis, severe mortality early on in the benthic stage of this species may limit the abundance of adult colonies. Most recruits of this species (∼80%) were at the primary polyp stage, and less than 1% of recruits were at stage of 4 polyps or more. We propose that biological disturbance, possibly by the presence of suspension-feeding brittle stars, and limited food supply in the deep sea may cause this mortality. Our findings reinforce the vulnerability of these corals to anthropogenic disturbances, such as trawling with mobile gear, and the importance of incorporating knowledge on processes during the early life history stages in conservation decisions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthozoa / classification
  • Anthozoa / growth & development*
  • Biodiversity*
  • Ecological and Environmental Phenomena*
  • Ecosystem
  • Life Cycle Stages*

Grants and funding

This study was funded by the National Science and Engineering Research Council (NSERC) through a Discovery Grant - ship time to AM (222932-06,372526-09) and the Canadian Healthy Oceans Network (340843-06). ML is the recipient of a Canada Graduate Scholarship (NSERC) and a fellowship from Dalhousie University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.